A preliminary X-ray study of a refolded PTS EIIB^fruc protein from Escherichia coli

The phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS) catalyzes the phosphorylation and transportation of its sugar substrates. A sugar-specific enzyme II complex involved in the PTS finally functions to translocate substrates across the membrane. A PTS EIIB^fruc protein, a fructose specific EIIB subunit, from Escherichia coli has been cloned, expressed, refolded, purified, and crystallized. The synchrotron data were collected to 2.6 Å from the crystal of a selenomethionine substitute PTS EIIB^fruc protein. The crystal belongs to the primitive trigonal space group P3₁21, with unit-cell parameters of a = 33.4 Å, b = 33.4 Å, c = 154.0 Å, and β = 120.0°. A full structure determination is under way to provide insights into the structure-function relationships of this protein.